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Finding the Fourth Proportional to 858.10, 1,287.47 and 280.97

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Solution

The fourth proportional to 858.10, 1,287.47 and 280.97 is: 421.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.10 : 1,287.47 = 280.97 : x
  2. Step 2: Convert to fraction form
    858.10/1,287.47 = 280.97/x
  3. Step 3: Cross multiply
    858.10x = 1,287.47 × 280.97
  4. Step 4: Simplify right side
    858.10x = 361,742.26
  5. Step 5: Solve for x
    x = 361,742.26/858.10
  6. Step 6: Final answer
    x = 421.56

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.